What R-448A is and where it is used
R-448A is a five-component zeotropic blend: R-32, R-125, R-1234yf, R-134a and R-1234ze(E), 26/26/20/21/7 by weight. It is sold as Solstice N40. Honeywell's data sheet describes it as a replacement for R-404A, R-507, R-22, the R-407 series and interim blends in low- and medium-temperature commercial refrigeration, in both new systems and retrofits, and says major equipment and component makers have approved it. Honeywell lists supermarket and convenience store freezers, coolers and display cases, cold storage warehouses and self-contained condensing units.
It is ASHRAE safety group A1 (nonflammable) with zero ozone depletion potential. Its 100-year GWP is 1,386 (AR4, as listed by EPA) or 1273 (AR5), which Honeywell puts at 68% below R-404A. Honeywell also claims 5 to 15% lower energy use and higher capacity than R-404A.
How to read the R-448A chart
R-448A has a large glide, so each temperature has a bubble (liquid) and a dew (vapor) pressure well apart. At 44 psig the dew point is 19.9°F and the bubble point is 9.2°F, a glide of 10.7°F.
- Superheat: always use the dew column. A cooler suction of 44 psig is 19.9°F. Subtract that from the suction line temperature.
- Subcooling: always use the bubble column. A liquid line reading of 260 psig converts to 104.7°F. Subtract the liquid line temperature from it.
Honeywell publishes its R-448A chart pressure-first to make the glide clear: at one coil pressure, the refrigerant starts boiling at the bubble temperature and finishes at the dew temperature. The superheat calculator and subcooling calculator pick the right column. See bubble point, dew point and glide for the background.
Example R-448A pressures in refrigeration
The figures below are worked examples at assumed coil temperatures, not targets for any system:
- Cooler: an evaporator at a 20°F dew point runs about 44.1 psig suction, against 55.3 psig for R-404A.
- Freezer: an evaporator at a -20°F dew point runs about 9.6 psig.
- Head: at 105°F and 115°F condensing (bubble) temperatures, head pressure is 261.1 psig and 299.6 psig.
National Refrigerants describes R-448A pressures as similar to or slightly below R-404A, and higher than R-22.
Retrofit and service notes
- Charge as liquid: National Refrigerants says R-448A must be removed from the cylinder as liquid to avoid fractionation, and that it can be added to a system during service without recovering the existing R-448A charge.
- Oil: Honeywell recommends POE and notes that compressor makers typically qualify specific lubricants. National Refrigerants says an R-404A system's existing POE is compatible, and an R-22 system needs its mineral oil changed to POE per the manufacturer.
- From R-404A: National Refrigerants says the existing expansion valve is suitable but should be closed 1 to 2 turns, then superheat adjusted. The final charge is about 105% of the R-404A charge.
- From R-22: expect higher pressures and lower discharge temperature. The final charge is about 95% of the R-22 charge. National recommends replacing seals during the retrofit, since old seals may leak once exposed to HFC refrigerant and POE.
- Recovery: National Refrigerants calls for a recovery cylinder rated for at least 300 psig service pressure.
Regulations
EPA's May 2026 amendments to the Technology Transitions rule set an interim GWP limit of 1,400 for new supermarket systems installed from January 1, 2027 and new remote condensing units installed from July 27, 2026. R-448A is under that limit, so the rule allows it in that new equipment until January 1, 2032. From then, limits of 150 or 300 apply depending on charge size and configuration. New cold storage warehouses have a 700 limit from July 27, 2026, and new stand-alone retail food units a 150 limit since 2025, so R-448A is out for both. EPA says existing systems can be serviced and repaired throughout their useful life.